Hi Tiggs
You do not have to have papers to compete in agility but the rules differ depending on the body organising the shows.
KC shows used to be the only shows but are not any more. To enter a KC show your dog needs to be registered with the KC. If you do not have breed papers you can register your dog on the working trials register. If you go to the kennel club website
www.the-kennel-club.org uk and do a search under working trials register you will find the information.
If you chose to compete at non KC "unaffiliated" shows then the rules differ according to the organisation. Most require you to register with that organisation eg UKA / EMDAC but sdo not require the dog to be a pedigree. I am not sure about most of these but if you look at show schedules they should say what they require for people to enter.
You can find details of up and coming shows at:
www.agilitynet.co.ukIf you train with a club they may have some forms for application for registration on the KC working trials or information on the organisations which run shows near to you, Some organisations are still quite limited in geographical areas where they run shows. Hope that this is clear and enjoy competing
Rosie